White-hot bolt from the blue

QUESTION Is a lightning bolt hotter than the Sun?

A lightning bolt can be five times hotter than the surface of the Sun, but is nowhere near as hot as the centre of the Sun.

Measuring the energy of lightning has been a challenge for scientists. Atmospheric physicists have created artificial lightning by firing rockets into thunderclouds. Using instruments on the ground to measure the temperature and electrical current from these artificial bolts, they have calculated that lightning measures between 20,000 and 30,000K (degrees Kelvin).

in 2016, Matthew A. Pasek and Marc hurst of the South Florida School of geosciences studied fulgurites, conical rods of glass that can be created when lightning strikes sand, and found that the stronger a lightning bolt, the greater the diameter of the rod.

they calculated that the energy produced by a lightning strike can heat the air temperature to more than 30,000K.

this exceeds the surface temperature of the Sun, which is 6,000K, estimated by measuring the wavelengths of light it emits.

At the sun’s core, however, plasma temperatures would hit 15 million K. K. Armstrong, Harrow, Middx.

QUESTION What is the bird on the RAF badge? I’ve seen it referred to as an eagle and an albatross.

the previous correspondent stated the cloth eagle is worn on the arm of other ranks, one facing forward and one facing back. this is incorrect.

Both eagles face the rear and they are issued in pairs. this is confirmed in the book Badges And Uniforms Of the RAF, by Malcolm C. hobart.

When i was in the RAF, one of the wags in the motor transport section reversed the badges on his great coat.

When he was demobbed three years later, his joke had gone unnoticed and the eagles were still flying forward.

Mike Tilyard, Yalding, Kent.